Question

		2. When a new floral shop opened, a record of the daily number of phone calls was kept. The records showed the following data. Let the number of calls be the random variable X. Use this summary to determine the probability that the number of phone calls is 2 per day. Number of calls per day Frequency 14 1/30 1/15 1/10 3/15 7/15 3. The manufacturer of a particular battery pack for laptop computers claims its battery packs can function for 9 hours, on the average, before having to be recharged. A competitor claims that the manufacturer's claim is too high. A random sample of 38 battery packs was selected and placed on test. The mean functioning time before having to be recharged was 7.5 hours with a standard deviation of 1.6 hours. Perform the appropriate test of hypothesis to determine whether the competitor is correct. Test using alpha = 0.05. Based on the test statistic, what can you conclude? Test statistic = -35.62500000, so we should not reject the manufacturer's claim Test statistic = -35.62500000, so we should reject the manufacturer's claim Test statistic = -7.310095755, so we should reject the manufacturer's claim. Test statistic = -5.779138128, so we should reject the manufacturer's claim. Test statistic = -5.779138128, so we should not reject the manufacturer's claim.

Answer 1

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2.
P(X = 2)

= Frequency for number of calls per day = 2 / total frequency

= 1/(2+1+9+3+14+1)

= 1/30